Astronomers in Japan used a supercomputer and a hypothetical neutron star to explain blinking, enigmatic objects known as Ultra Luminous X-ray pulsars.
Terzan 5 looks like an ordinary globular cluster, but has stars of hugely different ages. Some of its stars are similar to the Milky Way's most ancient stars.
Brown dwarfs are like stars, but too small to ignite fusion in their cores and so shine as stars do. If you saw one, it wouldn't be brown. It'd be magenta.